: The goal of this research is to understand the role of the motor cortex in controlling movement. Despite intense efforts over the last two centuries, there is still little consensus about the mechanisms by which the motor cortex controls voluntary movements. Recently, exploratory movements of the mystacial vibrissae ("whisking") have emerged as a promising, simpler model system for addressing this issue. However, progress has been limited by the lack of data on the pathways and mechanisms responsible for the motor act. Based on our findings, we hypothesize that pre-motoneurons in the parvocellular reticular formation are a key part of a network that controls exploratory whisking, and that the motor cortex modulates whisking by its action on these pre-motoneurons. Several hypotheses will be tested using electrophysilolgical and neuroanatomical approaches in vivo and in vitro. The proposed studies will provide data pertinent to understand the normal functions of the mortor cortex, and the processes underlying congenital or acquired neurological diseases resulting in sensory-motor deficits.